First get rid of the -3 by adding the opposite +3 to the 7 which makes it ten so now it’s x over 4 equals ten so next you make the ten to ten over one cause ten over one is still ten then you cross multiply so then it’s 10 times four equals x times one and then you solve the 10 times four which is 40 and x times one is 1x cause any number times x is just the number then x so now you have 40=1x and to get rid of the one you divide the number that’s by the x on both sides so 40 divided by one = 1x divided by 1 and the ones cancel out then you divide 40 by one which is 40 so X=40
